Mobile telephones of today are typically small and have a multitude of means for user input, including keypad keys, virtual keys on touch sensitive display screens as well as other buttons and dial-type means. These means for user input are usually distributed spatially all over the telephone and a user handling the telephone need always to be careful not to accidentally manipulate these input means, since this may lead to unwanted activation of telephone functions.
Telephones according to prior art are usually equipped with some sort of key lock function, which is selectively activated by a user through manual procedures such as selecting the key lock function from a menu by way of pressing a number of keys in a predetermined sequence. Needless to say, such a manual procedure has a drawback in that it is necessary for the user to remember to manually activate the key lock when, e.g., putting the telephone in his/her pocket or stowing the telephone in a bag etc.
Another way of locking the keys according to prior art is by means of an automatic time-out function. That is, the keys on the telephone are locked when a predetermined time interval has lapsed since any key has been pressed or manipulated. Such a solution has a drawback in that it is not very flexible in that the keys will be locked unconditionally, irrespective of the intentions and wishes of the user.